WO2023171518A1 - Optical film, optically anisotropic layer, alignment film-forming composition, method for producing optical film, polarizing plate, and image display device - Google Patents

Abstract

The present invention addresses the problem of providing: an optical film which has improved orientation of a liquid crystal compound in an optical anisotropic layer while suppressing the occurrence of bright spot defects; an optically anisotropic layer; an alignment film-forming composition; a method for producing an optical film; a polarizing plate; and an image display device. An optical film according to the present invention has an alignment film and an optically anisotropic layer, wherein: the optically anisotropic layer is a layer formed using an optically anisotropic layer-forming composition containing a polymerizable liquid crystal compound; and the alignment film is a film formed using an alignment film-forming composition containing an additive having a C5-C29 alkyl group and a polymer having no C5-C29 alkyl group.

Description

Optical film, optically anisotropic layer, alignment film forming composition, optical film manufacturing method, polarizing plate, and image display device

The present invention relates to an optical film, an optically anisotropic layer, a composition for forming an alignment film, a method for producing an optical film, a polarizing plate, and an image display device.

Optical films such as optical compensatory sheets and retardation films are used in various image display devices to eliminate image coloration or expand viewing angles.
A stretched birefringent film has been used as an optical film, but in recent years, it has been proposed to use an optical film having an optically anisotropic layer made of a liquid crystal compound in place of the stretched birefringent film.

When forming such an optically anisotropic layer, an alignment film is usually used.
For example, Patent Document 1 describes an embodiment in which an optically anisotropic layer is formed on an alignment film formed using a coating liquid containing polyvinyl alcohol having a specific group ([Claim 1] [ Claim 2] [Example]).

Japanese Patent Application Publication No. 9-152509

Incidentally, the alignment film is generally used after imparting an alignment regulating force through a rubbing process, but the alignment film debris generated during the rubbing process may cause the optically anisotropic layer to It is known that bright-spot defects may occur in optical films containing the same.
Therefore, the present inventors investigated the alignment film described in Patent Document 1 and found that the alignment of the liquid crystal compound in the optically anisotropic layer was good. Considering the standards for bright spot defects accompanying the diversification of uses for display devices, it was found that there is room for improvement in suppressing bright spot defects.

Therefore, an object of the present invention is to provide an optical film in which the orientation of a liquid crystal compound in an optically anisotropic layer is improved and the occurrence of bright spot defects is suppressed.
Another object of the present invention is to provide an optically anisotropic layer, a composition for forming an alignment film, a method for producing an optical film, a polarizing plate, and an image display device.

As a result of intensive studies to achieve the above object, the present inventors found that an alignment film containing an additive having an alkyl group having 5 to 29 carbon atoms and a polymer having no alkyl group having 5 to 29 carbon atoms. It has been discovered that by using an alignment film formed using a forming composition, the alignment of the liquid crystal compound in the optically anisotropic layer can be improved, and the occurrence of bright spot defects in the optical film can be suppressed, and the present invention has been achieved. completed.
That is, the present inventors have found that the above problem can be solved by the following configuration.

[1] An optical film having an alignment film and an optically anisotropic layer,
The optically anisotropic layer is a layer formed using an optically anisotropic layer forming composition containing a polymerizable liquid crystal compound,
The alignment film is a film formed using an alignment film-forming composition containing an additive having an alkyl group having 5 to 29 carbon atoms and a polymer having no alkyl group having 5 to 29 carbon atoms. , optical film.
[2] The optical film according to [1], wherein the additive has a hydrophilic group.
[3] The optical film according to [1] or [2], wherein the additive has an alkyl group having 12 to 22 carbon atoms.
[4] The optical film according to any one of [1] to [3], wherein the polymer is polyvinyl alcohol or modified polyvinyl alcohol.
[5] An optically anisotropic layer formed using an optically anisotropic layer forming composition containing a polymerizable liquid crystal compound,
In the optically anisotropic layer, there are 1 to 80 bright spot defects/10 ^m2 of 100 μm or more, and the nucleus of the bright spot defects is formed by an additive having an alkyl group with a carbon number of 5 to 29 and a carbon number of 1 to 80/10 m2. An optically anisotropic layer containing a polymer having 5 to 29 alkyl groups.
[6] The optically anisotropic layer according to [5], wherein the additive has a hydrophilic group.
[7] The optically anisotropic layer according to [5] or [6], wherein the additive has an alkyl group having 12 to 22 carbon atoms.
[8] The optically anisotropic layer according to any one of [5] to [7], wherein the polymer is polyvinyl alcohol or modified polyvinyl alcohol.
[9] A composition for forming an alignment film containing an additive having an alkyl group having 5 to 29 carbon atoms and a polymer having no alkyl group having 5 to 29 carbon atoms.
[10] The composition for forming an alignment film according to [9], wherein the additive has a hydrophilic group.
[11] The composition for forming an alignment film according to [9] or [10], wherein the additive has an alkyl group having 12 to 22 carbon atoms.
[12] The composition for forming an alignment film according to any one of [9] to [11], wherein the polymer is polyvinyl alcohol or modified polyvinyl alcohol.
[13] An alignment film forming step of forming an alignment film on a support using the composition for forming an alignment film according to any one of [9] to [12];
a rubbing process in which the alignment film is rubbed;
an optically anisotropic layer forming step of forming an optically anisotropic layer on an alignment film subjected to a rubbing treatment using an optically anisotropic layer forming composition containing a polymerizable liquid crystal compound;
A method for producing an optical film, comprising:
[14] A polarizing plate comprising the optical film according to any one of [1] to [4] or the optically anisotropic layer according to any one of [5] to [8], and a polarizer.
[15] An image display device comprising the optical film according to any one of [1] to [4] or the optically anisotropic layer according to any one of [5] to [8].
[16] The image display device according to [15], which is a liquid crystal display device.
[17] The image display device according to [15], which is an organic EL display device.

According to the present invention, it is possible to provide an optical film in which the orientation of the liquid crystal compound in the optically anisotropic layer is improved and the occurrence of bright spot defects is suppressed.
Further, according to the present invention, an optically anisotropic layer, a composition for forming an alignment film, a method for producing an optical film, a polarizing plate, and an image display device can be provided.

The present invention will be explained in detail below.
Although the description of the constituent elements described below may be made based on typical embodiments of the present invention, the present invention is not limited to such embodiments.
Note that in this specification, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as the lower limit and upper limit.
Moreover, in this specification, each component may be a substance corresponding to each component, which may be used alone or in combination of two or more. Here, when two or more types of substances are used together for each component, the content of the component refers to the total content of the substances used in combination, unless otherwise specified.
Further, in this specification, "(meth)acrylate" is a notation representing "acrylate" or "methacrylate", "(meth)acrylic" is a notation representing "acrylic" or "methacrylic", and "(meth)acrylate" is a notation representing "acrylic" or "methacrylic";(Meth)acryloyl" is a notation representing "acryloyl" or "methacryloyl."
In addition, in this specification, the bonding direction of the divalent group (for example, -CO-O-) is not particularly limited unless the bonding position is specified, and for example, XL- If L in Y is -COO-, the position bonded to the X side is *1 and the position bonded to the Y side is *2, then L is *1-O-CO-*2. It may be *1-CO-O-*2.

[Optical film]
The optical film of the present invention has an alignment film and an optically anisotropic layer.
Further, the optically anisotropic layer included in the optical film of the present invention is a layer formed using an optically anisotropic layer forming composition containing a polymerizable liquid crystal compound.
Further, the alignment film of the optical film of the present invention is a composition for forming an alignment film containing an additive having an alkyl group having 5 to 29 carbon atoms and a polymer having no alkyl group having 5 to 29 carbon atoms. This is a film formed using

In the present invention, as described above, an additive having an alkyl group having 5 to 29 carbon atoms (hereinafter also referred to as "specific additive") and a polymer having no alkyl group having 5 to 29 carbon atoms (hereinafter referred to as "specific additive") are used. By using an alignment film formed using an alignment film-forming composition containing (also abbreviated as "specific polymer"), the alignment of the liquid crystal compound in the optically anisotropic layer is improved, and the optical The occurrence of bright spot defects in the film can be suppressed.
The reason why these effects occur is not clear in detail, but the present inventors speculate as follows.
In other words, by using a specific additive as a component of the composition for forming an alignment film, the friction between the alignment film and the pile of the rubbing cloth used when rubbing the alignment film is reduced, and the generation of debris from the alignment film is reduced. It is thought that because the amount of dust could be reduced, the occurrence of bright spot defects could be suppressed. This can also be inferred from the measured values of the dynamic friction coefficient of the alignment film shown in Table 1 of Examples described later.
In addition, since the specific additive has an alkyl group having 5 to 29 carbon atoms, it has good compatibility with the specific polymer, suppresses aggregation of the specific additives, and as a result, the surface of the alignment film It is thought that because the specific polymer could be exposed appropriately, the alignment of the liquid crystal compound in the optically anisotropic layer formed on the alignment film was improved.
Hereinafter, the alignment film and the optically anisotropic layer included in the optical film of the present invention will be explained in detail.

[Alignment film]
The alignment film of the optical film of the present invention contains an additive having an alkyl group having 5 to 29 carbon atoms (specific additive) and a polymer having no alkyl group having 5 to 29 carbon atoms (specific polymer). This is a film formed using a composition for forming an alignment film.

<Specific additives>
The specific additive contained in the composition for forming an alignment film is an additive having an alkyl group having 5 to 29 carbon atoms.
Here, examples of the alkyl group include pentyl group, hexyl group, heptyl group, octyl group, 2-ethylhexyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, hexadecyl group (cetyl group), octadecyl group, icosyl group, docosyl group, tetracosyl group, hexacosyl group, nonacosyl group, and the like.
Further, the alkyl group may be a linear alkyl group or a branched alkyl group, but is preferably a linear alkyl group.

In the present invention, the number of carbon atoms in the alkyl group is preferably 10 to 25, more preferably 12 to 22, because the alignment of the liquid crystal compound in the optically anisotropic layer is better. .

The specific additive preferably has a hydrophilic group in addition to the alkyl group, since this improves the alignment of the liquid crystal compound in the optically anisotropic layer.
The hydrophilic group is not particularly limited, and both ionic hydrophilic groups (anionic hydrophilic groups, cationic hydrophilic groups, and amphoteric hydrophilic groups) and nonionic hydrophilic groups can be used. can.
Examples of the anionic hydrophilic group include a hydroxy group, a carboxy group, a carboxylate, a sulfonic acid group, a sulfonate, a sulfuric acid ester salt, a phosphoric acid group, and a phosphoric acid ester salt.
Examples of the cationic hydrophilic group include an amino group and a quaternary ammonium salt.
The nonionic hydrophilic group may be any of the ester type, ether type, ester-ether type, and alkanolamide type, preferably the ether type, and the nonionic hydrophilic group (e.g., polyoxyalkylene group) (ethylene group, polyoxypropylene group, polyoxyalkylene group in which an oxyethylene group and an oxypropylene group are block or randomly bonded) are more preferable.

Among these hydrophilic groups, ionic hydrophilic groups (limited to neutralized products such as carboxylic acid salts) and nonionic hydrophilic groups are used because they can further suppress the occurrence of bright spot defects in optical films. It is preferable that it is a group.

In the present invention, the specific additive may be a low molecular compound or a high molecular compound.
Here, the term "low molecular compound" refers to a specific additive having a molecular weight of 100 or more and less than 2,000.
Further, the term "polymer compound" refers to a specific additive having a molecular weight of 2000 or more, and the weight average molecular weight (Mw) is preferably 10000 to 40000, more preferably 11000 to 39000, More preferably, it is 13,000 to 35,000. When the weight average molecular weight is 10,000 or more, unevenness is suppressed during formation of the liquid crystal cured layer, and when the weight average molecular weight is 40,000 or less, the orientation of the liquid crystal cured layer becomes better.

Furthermore, in the present invention, the specific additive is preferably a polymer compound because it has a lower coefficient of friction, that is, can maintain orientation while suppressing bright spot defects. The clear mechanism by which the above effects are obtained by being a high molecular compound is not clear, but because high molecular compounds form entanglements while being compatible with specific polymers described below, they tend to aggregate more easily than low molecular compounds. It is assumed that this is because it is difficult to coat the surface of the alignment film and can coat the surface of the alignment film uniformly. Further, a high molecular compound is preferable to a low molecular compound in that it is more robust in the process of forming an alignment film, that is, the change in the coefficient of dynamic friction with respect to the drying temperature is smaller. This is presumed to be because, in the case of a polymer compound that has good compatibility with the specific polymer described below, the change in compatibility with the specific polymer due to the drying temperature is small, and therefore the change in the amount of surface coverage due to the drying temperature is small.

Specific examples of the low-molecular compound having the above-mentioned alkyl group and any hydrophilic group include sodium dodecyl sulfate, polyoxyethylene (10) cetyl ether, polyoxyethylene (20) docosyl ether, and tetrahexyl ether. Examples include ammonium bromide, tetra-n-octylammonium bromide, trimethylstearylammonium bromide, melisic acid, and the like.

Examples of the polymer compound having the above-mentioned alkyl group and any hydrophilic group include a polymer having the above-mentioned alkyl group and hydrophilic group in the side chain of a (meth)acrylic polymer.
Such polymers include a side chain having the above-mentioned alkyl group (hereinafter also abbreviated as "hydrophobic part") and a side chain having the above-mentioned hydrophilic group (hereinafter also abbreviated as "hydrophilic part"). A copolymer having these in separate repeating units is preferred.
Here, the hydrophobic part is not particularly limited as long as it has the above-mentioned alkyl group, but it has a polyoxyalkylene group as a linking group on the main chain side and an alkyl group having 12 to 22 carbon atoms on the terminal side. It is preferable to have one.
Further, the hydrophilic part is not particularly limited as long as it has the above-mentioned hydrophilic group, but it is preferably a side chain having a polyoxyalkylene group, more preferably a side chain having a polyoxyethylene group. preferable.

Examples of monomers that form such a hydrophobic part include those shown below.

Furthermore, examples of monomers that form such a hydrophilic part include those shown below.

In the present invention, the content of the specific additive contained in the composition for forming an alignment film is preferably 0.1 to 10% by mass, and preferably 0.15 to 8% by mass based on the mass of the specific polymer described below. %, and even more preferably 0.20 to 5% by mass.
Similarly, the content of the specific additive contained in the alignment film to be formed is preferably 0.1 to 10% by mass, and preferably 0.15 to 8% by mass, based on the mass of the specific polymer described below. The amount is more preferably 0.20 to 5% by mass.

<Specific polymer>
The specific polymer contained in the composition for forming an alignment film is a polymer having 5 to 29 carbon atoms and having no alkyl group.
Here, the specific polymer is not particularly limited as long as it does not have an alkyl group having 5 to 29 carbon atoms, and includes, for example, polyvinyl alcohol (polyvinyl acetate), polystyrene, polyester, polyamide, polysulfone, polyethersulfone, polyimide, Examples include polyacrylic acid, poly(meth)acrylate, polyacetal, polycarbonate, and modified polymers thereof.

Further, the weight average molecular weight of the specific polymer is not particularly limited, and is preferably from 5,000 to 200,000, more preferably from 10,000 to 70,000.
Here, the weight average molecular weight in the present invention is a value measured by gel permeation chromatography (GPC) under the conditions shown below.
・Solvent (eluent): THF (tetrahydrofuran)
・Device name: TOSOH HLC-8320GPC
・Column: 3 TOSOH TSKgel Super HZM-H (4.6 mm x 15 cm) connected together ・Column temperature: 40°C
・Sample concentration: 0.1% by mass
・Flow rate: 1.0ml/min
・Calibration curve: Use the calibration curve of 7 samples of TOSOH TSK standard polystyrene Mw=2800000 to 1050 (Mw/Mn=1.03 to 1.06)

In the present invention, the specific polymer is preferably polyvinyl alcohol or modified polyvinyl alcohol because the orientation of the liquid crystal compound in the optically anisotropic layer is better and the generation of bright spot defects in the optical film can be further suppressed. preferable.
Here, polyvinyl alcohol is obtained by hydrolyzing all the acetyl groups that a vinyl acetate polymer has with a strong base such as sodium hydroxide to convert them into hydroxyl groups (saponification).
Moreover, modified polyvinyl alcohol is obtained by substituting the above-mentioned hydroxyl group with another substituent (for example, an acetyl group, a carboxy group, an amide group, etc.).

Examples of modified polyvinyl alcohols include polymers having repeating units represented by the following formula (1) and repeating units represented by the following formula (2), and polymers having repeating units represented by the following formula (1) and repeating units represented by the following formula (1). Examples include polymers having a repeating unit represented by the following formula (2) and a repeating unit represented by the following formula (3).

In the above formula (3), L is -CO-, -O-, -S-, -C(=S)-, -CR ¹ R ² -, -CR ³ =CR ⁴ -, -NR ⁵ -, Alternatively, it represents a divalent linking group consisting of a combination of two or more of these, and R ¹ to R ⁵ each independently represent a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 5 carbon atoms.

R represents an alkyl group having 1 to 5 carbon atoms, a phenyl group, a heteroaryl group, a polymerizable group, or a combination of two or more of these groups.
The alkyl group may be linear or branched. Further, the alkyl group may have a cyclic structure.
The number of carbon atoms in the alkyl group is not particularly limited as long as it is 1 to 5, but 2 to 4 is preferred.
The alkyl group may have a hydroxyl group. That is, the alkyl group may have a hydroxyl group as a substituent.
Furthermore, the alkyl group may contain a heteroatom. Examples of the heteroatom include an oxygen atom, a nitrogen atom, and a sulfur atom. When the alkyl group contains a heteroatom, for example, -O-, -CO-O-, -CO-NH-, -SO ₂ -, -SO ₂ -O-, and -SO ₂ -NH Examples include embodiments containing divalent linking groups such as -.
As the heteroaryl group, a heteroaryl group consisting of a 5-, 6-, or 7-membered ring or a condensed ring thereof is preferred. Examples of the heteroatom contained in the heteroaryl group include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of rings constituting the heteroaryl group include furan ring, thiophene ring, pyrrole ring, pyrroline ring, pyrrolidine ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, and imidazoline ring. can be mentioned.
Examples of the polymerizable group include polymerizable groups represented by any of the following formulas (P-1) to (P-20) explained in the polymerizable liquid crystal compound described below.

Although the content of the repeating unit represented by the above formula (1) is not particularly limited, it is preferably 76.0 to 95.0 mol%, and 78.0 to 91.0% by mole, based on the total repeating units in the modified polyvinyl alcohol. 0 mol% is more preferred.

The content of the repeating unit represented by the above formula (2) is not particularly limited, but it is preferably more than 0 mol% and 25.0 mol% or less, and 1.0 to 21% by mole, based on the total repeating units in the modified polyvinyl alcohol. .0 mol% is more preferred.

When the modified polyvinyl alcohol has a repeating unit represented by the above formula (3), the content of the repeating unit represented by the above formula (3) is not particularly limited, but all repeating units in the modified polyvinyl alcohol It is preferably 0.5 to 14.0 mol%.

<Other ingredients>
The composition for forming an alignment film may contain components other than the above-mentioned specific additives and specific polymers.

(Polymerization initiator)
When the above-mentioned specific polymer (e.g., modified polyvinyl alcohol, etc.) has a polymerizable group (e.g., (meth)acryloyl group, etc.), the composition for forming an alignment film must contain a polymerization initiator. is preferred.
The polymerization initiator is not particularly limited, and examples thereof include thermal polymerization initiators and photopolymerization initiators depending on the type of polymerization reaction.
As the polymerization initiator, a photopolymerization initiator that can initiate a polymerization reaction by ultraviolet irradiation is preferred.
Examples of photopolymerization initiators include α-carbonyl compounds, acyloin ethers, α-hydrocarbon-substituted aromatic acyloin compounds, polynuclear quinone compounds, combinations of triarylimidazole dimer and p-aminophenyl ketone, acridine and phenazine compounds. , oxadiazole compounds, and acylphosphine oxide compounds.

(hardening agent)
The composition for forming an alignment film may contain a curing agent in addition to the above-mentioned specific additives.
Examples of the curing agent include carboxylic acid compounds (eg, citric acid esters, etc.), aldehyde compounds (eg, glutaraldehyde, glyoxal, etc.), and the like.

(solvent)
The composition for forming an alignment film preferably contains a solvent from the viewpoint of workability when forming an alignment film.
Examples of solvents include ketones (e.g., acetone, 2-butanone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone), ethers (e.g., dioxane, and tetrahydrofuran), aliphatic hydrocarbons (e.g., hexane), cycloaliphatic hydrocarbons (e.g. cyclohexane), aromatic hydrocarbons (e.g. toluene, xylene, and trimethylbenzene), halogenated carbons (e.g. dichloromethane, dichloroethane, dichlorobenzene, and chloro toluene), esters (e.g. methyl acetate, ethyl acetate, and butyl acetate), water, alcohols (e.g. ethanol, isopropanol, butanol, and cyclohexanol), cellosolves (e.g. methyl cellosolve, and ethyl cellosolve), cellosolve acetates, sulfoxides (eg, dimethyl sulfoxide), amides (eg, dimethylformamide, and dimethylacetamide).
One type of solvent may be used alone, or two or more types may be used in combination.

The alignment film is a film formed using the composition for forming an alignment film containing the above-mentioned specific additive and specific polymer, and the manufacturing procedure thereof will be described later in the alignment film formation method of the optical film manufacturing method of the present invention. The process will be explained in detail.

The thickness of the alignment film is not particularly limited, but is preferably 0.2 to 1.0 μm, more preferably 0.4 to 0.8 μm.

[Optically anisotropic layer]
The optically anisotropic layer of the optical film of the present invention is a layer disposed on the above-mentioned alignment film, and in the present invention, an optically anisotropic layer-forming composition containing a polymerizable liquid crystal compound is used. This is a layer formed by More specifically, in the coating film formed by applying the composition for forming an optically anisotropic layer, as detailed in the optically anisotropic layer forming step of the method for producing an optical film of the present invention described later. It is preferable that the layer be formed by aligning the polymerizable liquid crystal compound and fixing that state. In this case, it is no longer necessary to exhibit liquid crystallinity after forming the layer.

<Polymerizable liquid crystal compound>
The polymerizable liquid crystal compound contained in the composition for forming an optically anisotropic layer is a liquid crystal compound having a polymerizable group.
Here, the polymerizable group is not particularly limited, but preferably a polymerizable group capable of radical polymerization or cationic polymerization.
As the radically polymerizable group, a known radically polymerizable group can be used, and preferred examples include an acryloyloxy group or a methacryloyloxy group. In this case, it is known that an acryloyloxy group generally has a high polymerization rate, and an acryloyloxy group is preferred from the viewpoint of improving productivity, but a methacryloyloxy group can also be used as a polymerizable group.
As the cationic polymerizable group, a known cationic polymerizable group can be used, and specifically, an alicyclic ether group, a cyclic acetal group, a cyclic lactone group, a cyclic thioether group, a spiro-orthoester group, and a vinyloxy Examples include groups. Among these, an alicyclic ether group or a vinyloxy group is preferred, and an epoxy group, an oxetanyl group, or a vinyloxy group is particularly preferred.
Particularly preferred examples of polymerizable groups include polymerizable groups represented by any of the following formulas (P-1) to (P-20).

The polymerizable liquid crystal compound is not particularly limited, and includes, for example, a compound capable of homeotropic alignment, homogeneous alignment, hybrid alignment, and cholesteric alignment.
Generally, liquid crystal compounds can be classified into rod-like types and disc-like types based on their shapes. Furthermore, there are low-molecular and high-molecular types, respectively. Polymers generally refer to those with a degree of polymerization of 100 or more (Polymer Physics/Phase Transition Dynamics, Masao Doi, p. 2, Iwanami Shoten, 1992). In the present invention, any liquid crystal compound can be used, but a rod-shaped liquid crystal compound or a discotic liquid crystal compound (discotic liquid crystal compound) is preferable. Further, a monomer or a relatively low molecular weight liquid crystal compound having a degree of polymerization of less than 100 is preferable.

As the rod-shaped liquid crystal compound, for example, those described in claim 1 of Japanese Patent Publication No. 11-513019 or paragraphs [0026] to [0098] of JP-A-2005-289980 are preferable, and as the discotic liquid crystal compound, For example, those described in paragraphs [0020] to [0067] of JP-A-2007-108732 or paragraphs [0013] to [0108] of JP-A-2010-244038 are preferred.

As the polymerizable liquid crystal compound, a reverse wavelength dispersion liquid crystal compound can be used.
Here, in this specification, a liquid crystal compound with "reverse wavelength dispersion" refers to the in-plane retardation (Re) value measured at a specific wavelength (visible light range) of a retardation film made using this compound. In other words, as the measurement wavelength becomes larger, the Re value becomes the same or becomes higher.

The reverse wavelength dispersion liquid crystal compound is not particularly limited as long as it can form a reverse wavelength dispersion film as described above. (especially the compounds described in paragraphs [0034] to [0039]), the compounds represented by the general formula (1) described in JP-A-2010-084032 (especially the compounds described in paragraphs [0067] to [0073]) ), and the compound represented by the general formula (1) described in JP-A-2016-081035 (particularly the compounds described in paragraphs [0043] to [0055]).
Additionally, paragraphs [0027] to [0100] of JP2011-006360, paragraphs [0028] to [0125] of JP2011-006361, and paragraphs [0034] to [0034] of JP2012-207765. 0298], paragraphs [0016] to [0345] of JP2012-077055, paragraphs [0017] to [0072] of WO12/141245, paragraphs [0021] to [0088] of WO12/147904, Examples include compounds described in paragraphs [0028] to [0115] of WO14/147904.

<Polymerization initiator>
The composition for forming an optically anisotropic layer preferably contains a polymerization initiator.
Examples of the polymerization initiator include those explained in connection with the composition for forming an alignment film mentioned above.

<Solvent>
The composition for forming an optically anisotropic layer preferably contains a solvent from the viewpoint of workability when forming an optically anisotropic layer.
Examples of the solvent include those explained in connection with the composition for forming an alignment film mentioned above.

<Leveling agent>
The composition for forming an optically anisotropic layer preferably contains a leveling agent from the viewpoint of keeping the surface of the optically anisotropic layer smooth and facilitating orientation control.
As such a leveling agent, a fluorine-based leveling agent or a silicon-based leveling agent is preferable because it has a high leveling effect with respect to the amount added, and a fluorine-based leveling agent is more preferable because it is less likely to cause weeping (bloom, bleed). .
Examples of the leveling agent include compounds described in paragraphs [0079] to [0102] of JP-A No. 2007-069471, and compounds represented by the general formula (I) described in JP-A No. 2013-047204. (especially the compounds described in paragraphs [0020] to [0032]), compounds represented by the general formula (I) described in JP-A-2012-211306 (especially the compounds described in paragraphs [0022] to [0029]) (compounds described in JP-A No. 2002-129162), liquid crystal alignment promoters represented by general formula (I) described in JP-A No. 2002-129162 (particularly in paragraphs [0076] to [0078] and [0082] to [0084] compounds represented by general formulas (I), (II) and (III) described in JP-A No. 2005-099248 (particularly those described in paragraphs [0092] to [0096] compounds), etc. Note that the leveling agent may also have a function as an alignment control agent, which will be described later.

<Orientation control agent>
The composition for forming an optically anisotropic layer may contain an alignment control agent, if necessary.
By using an alignment control agent, it is possible to form various alignment states such as homogeneous alignment, homeotropic alignment (vertical alignment), tilted alignment, hybrid alignment, and cholesteric alignment, and it is also possible to form a specific alignment state more uniformly and precisely. It can be controlled and realized.

As the alignment control agent that promotes homogeneous alignment, for example, a low-molecular alignment control agent and a polymeric alignment control agent can be used.
Examples of low-molecular alignment control agents include paragraphs [0009] to [0083] of JP-A No. 2002-20363, paragraphs [0111] to [0120] of JP-A No. 2006-106662, and paragraphs [0111] to [0120] of JP-A No. 2006-106662, and JP-A No. 2012-2012. The descriptions in paragraphs [0021] to [0029] of Publication No.-211306 can be referred to, and the contents thereof are incorporated into the present specification.
In addition, for polymer alignment control agents, please refer to paragraphs [0021] to [0057] of JP-A No. 2004-198511 and paragraphs [0121] to [0167] of JP-A No. 2006-106662, for example. and the contents thereof are incorporated herein.

Furthermore, examples of the alignment control agent that forms or promotes homeotropic alignment include boronic acid compounds and onium salt compounds. Examples of this alignment control agent include paragraphs [0023] to [0032] of JP-A No. 2008-225281, paragraphs [0052]-[0058] of JP-A No. 2012-208397, and paragraphs [0052] to [0058] of JP-A No. 2008-026730. The compounds described in paragraphs [0024] to [0055] and paragraphs [0043] to [0055] of JP-A-2016-193869 can be referred to, and the contents thereof are incorporated into the present specification.

On the other hand, cholesteric alignment can be achieved by adding a chiral agent to the composition for forming an optically anisotropic layer, and the direction of rotation of the cholesteric alignment can be controlled depending on the direction of the chirality.
Note that the pitch of cholesteric alignment may be controlled depending on the alignment regulating force of the chiral agent.

When the composition for forming an optically anisotropic layer contains an alignment control agent, the content is preferably 0.01 to 10% by mass, and 0.05 to 5% by mass based on the total solid mass in the composition. More preferred. When the content is within this range, precipitation, phase separation, orientation defects, etc. can be suppressed while realizing a desired orientation state, and a uniform and highly transparent cured product can be obtained.

<Other ingredients>
The composition for forming an optically anisotropic layer may contain components other than those mentioned above. Other components include, for example, surfactants, tilt angle control agents, alignment aids, plasticizers, and crosslinking agents. Moreover, an ionic compound, a conductive polymer, etc. may be included as an antistatic agent.

The optically anisotropic layer is a film formed using the composition for forming an optically anisotropic layer described above, and the manufacturing procedure thereof will be described later in the optically anisotropic layer of the method for manufacturing an optical film of the present invention. This will be explained in detail in the forming process.

The thickness of the optically anisotropic layer is not particularly limited, but from the viewpoint of making the device thinner, it is preferably 0.7 to 2.5 μm, more preferably 0.9 to 2.2 μm.

The orientation state of the polymerizable liquid crystal compound in the optically anisotropic layer may be any of horizontal orientation, vertical orientation, tilted orientation, and twisted orientation, and the orientation state is horizontal to the main surface of the optically anisotropic layer. It is preferable that it is immobilized in an oriented state.
In this specification, "horizontal alignment" means that the main surface of the optically anisotropic layer and the long axis direction of the polymerizable liquid crystal compound are parallel. Note that it is not required that they be strictly parallel, and in this specification, the orientation is such that the angle between the long axis direction of the polymerizable liquid crystal compound and the main surface of the optically anisotropic layer is less than 10°. shall mean.
In the optically anisotropic layer, the angle between the long axis direction of the polymerizable liquid crystal compound and the main surface of the optically anisotropic layer is preferably 0 to 5°, more preferably 0 to 3°, and preferably 0 to 2°. More preferred.

The optically anisotropic layer is more preferably a positive A plate or a positive C plate, and even more preferably a positive A plate.

Here, the positive A plate (positive A plate) and the positive C plate (positive C plate) are defined as follows.
The refractive index in the in-plane slow axis direction (direction where the in-plane refractive index is maximum) is nx, the refractive index in the direction orthogonal to the in-plane slow axis is ny, and the refraction in the thickness direction is When the ratio is nz, the positive A plate satisfies the relationship of formula (A1), and the positive C plate satisfies the relationship of formula (C1). Note that the positive A plate has a positive Rth value, and the positive C plate has a negative Rth value.
Formula (A1) nx>ny≒nz
Formula (C1) nz>nx≒ny
In addition, the above-mentioned "≒" includes not only the case where both are completely the same, but also the case where both are substantially the same.
Regarding this "substantially the same", for the positive A plate, for example, when (ny-nz) x d (where d is the thickness of the film) is -10 to 10 nm, preferably -5 to 5 nm. is also included in "ny≈nz", and a case where (nx-nz)×d is -10 to 10 nm, preferably -5 to 5 nm is also included in "nx≈nz". Furthermore, in the case of a positive C plate, for example, the case where (nx - ny) x d (where d is the thickness of the film) is 0 to 10 nm, preferably 0 to 5 nm is also included in "nx≒ny". .

When the optically anisotropic layer is a positive A plate, from the viewpoint of functioning as a λ/4 plate, Re (550) is preferably 100 to 180 nm, more preferably 120 to 160 nm, and 130 to 150 nm. The wavelength is more preferably 130 to 145 nm, particularly preferably 130 to 145 nm.
Here, the "λ/4 plate" is a plate that has a λ/4 function, specifically, the function of converting linearly polarized light of a certain wavelength into circularly polarized light (or from circularly polarized light to linearly polarized light). It is a board with

[Support]
The optical film of the present invention may have a support for supporting the above-mentioned alignment film.
The type of support is not particularly limited, and any known support can be used. In particular, a transparent support is preferred. Note that the transparent support is intended to be a support having a visible light transmittance of 60% or more, and the transmittance is preferably 80% or more, more preferably 90% or more.

Examples of the support include glass substrates and polymer films.
Materials for the polymer film include cellulose polymers; acrylic polymers containing acrylic acid ester polymers such as polymethyl methacrylate and lactone ring-containing polymers; thermoplastic norbornene polymers; polycarbonate polymers; polyethylene terephthalate, and polyethylene ester polymers; Polyester polymers such as phthalates; Styrenic polymers such as polystyrene and acrylonitrile styrene copolymers; Polyolefin polymers such as polyethylene, polypropylene, and ethylene-propylene copolymers; Vinyl chloride polymers; Nylon, aromatic polyamides, etc. Amide polymer; Imide polymer; Sulfone polymer; Polyether sulfone polymer; Polyether ether ketone polymer; Polyphenylene sulfide polymer; Vinylidene chloride polymer; Vinyl alcohol polymer; Vinyl butyral polymer; Arylate polymer; Examples include oxymethylene polymers; epoxy polymers; and polymers obtained by mixing these polymers.
Further, the support is preferably one that is removable.

[Optically anisotropic layer]
The optically anisotropic layer of the present invention is a layer formed using an optically anisotropic layer forming composition containing a polymerizable liquid crystal compound.
Further, in the optically anisotropic layer of the present invention, there are 1 to 80 bright spot defects/10 ^m2 with a diameter of 100 μm or more, and the nucleus of the bright spot defects has an alkyl group having 5 to 29 carbon atoms. It contains an additive and a polymer having 5 to 29 carbon atoms and no alkyl group.

Here, the number of bright spot defects of 100 μm or more existing in the optically anisotropic layer can be confirmed by the following method.
First, two polarizing plates are stacked on the Scherkasten in a crossed nicol state, and an optical film (observation area: 100 x 130 cm) having an optically anisotropic layer is sandwiched between the two polarizing plates, and light is emitted from the Scherkasten. Transmit.
Next, the optical film is observed from above the polarizing plate using a magnifying glass, and defects with a diameter of 100 μm or more are marked.
Next, a cross section is cut with a microtome so as to pass through the center of the marked defect, and an optical microscope observation is performed from the cross-sectional direction to count defects in which foreign matter is observed in the optically anisotropic layer.

As mentioned above, the nucleus of the bright spot defect existing in the optically anisotropic layer of the present invention is caused by the additive having an alkyl group having 5 to 29 carbon atoms and the polymer having no alkyl group having 5 to 29 carbon atoms. Contains.
Here, the above-mentioned additive and the above-mentioned polymer are respectively the same as the specific additive and specific polymer explained in the above-mentioned alignment film.
In other words, the nucleus of the bright spot defect existing in the optically anisotropic layer of the present invention is caused by the slight amount of debris of the alignment film generated when the alignment film is rubbed. It is thought that it has shifted to the tropic layer side.

[Composition for forming alignment film]
The composition for forming an alignment film of the present invention is a composition containing an additive having an alkyl group having 5 to 29 carbon atoms and a polymer having no alkyl group having 5 to 29 carbon atoms.
Here, the above-mentioned additive and the above-mentioned polymer are respectively the same as the specific additive and specific polymer explained in the above-mentioned alignment film.

[Optical film manufacturing method]
The method for producing an optical film of the present invention includes an alignment film forming step of forming an alignment film on a support using the composition for forming an alignment film of the present invention, and a rubbing step of subjecting the alignment film to a rubbing treatment. , a manufacturing method comprising an optically anisotropic layer forming step of forming an optically anisotropic layer on an alignment film subjected to a rubbing treatment using an optically anisotropic layer forming composition containing a polymerizable liquid crystal compound. It is.
Below, the procedure of each step will be explained in detail.

[Alignment film formation process]
The alignment film forming step is a step of forming an alignment film on a support using a composition for forming an alignment film.
The composition for forming an alignment film and the support used in this step are as described above.

One aspect of the specific procedure for forming an alignment film is to apply a composition for forming an alignment film onto a support, form a coating film on the support, and then subject the coating film to a rubbing treatment. An example of this method is to form an alignment film using the following method.
The method of applying the composition for forming an alignment film onto the support is not particularly limited, and examples thereof include wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, and die coating method. .
After applying the composition for forming an alignment film onto a support, the support coated with the composition for forming an alignment film may be subjected to a drying treatment to remove the solvent, if necessary.

[Rubbing process]
The rubbing process is a process of subjecting the alignment film to a rubbing process.
Here, for the rubbing treatment, a treatment method that is widely adopted as a liquid crystal alignment treatment process for liquid crystal display devices can be applied. That is, a method is used to obtain orientation by rubbing the surface of the orientation film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber, or the like.

[Optically anisotropic layer formation process]
The optically anisotropic layer forming step is a step of forming an optically anisotropic layer on an alignment film that has been subjected to a rubbing treatment using a composition for forming an optically anisotropic layer.

One aspect of the specific procedure for forming an optically anisotropic layer is to apply a composition for forming an optically anisotropic layer onto an alignment film, form a coating film on the alignment film, and apply the composition in the coating film. After aligning the polymerizable liquid crystal compound, the coating film may be subjected to a curing treatment to form an optically anisotropic layer.
Examples of the method for applying the composition for forming an optically anisotropic layer on the alignment film include the same method as the method for applying the composition for forming an alignment film described above.
After coating the composition for forming an optically anisotropic layer on the alignment film, if necessary, the support coated with the composition for forming an optically anisotropic layer is subjected to a drying treatment to remove the solvent. May be implemented.

The method for orienting the polymerizable liquid crystal compound in the coating film (orientation treatment) is not particularly limited, and examples thereof include a method of heating the coating film and a method of drying the coating film at room temperature. In the case of a thermotropic liquid crystal compound, the liquid crystal phase formed by the alignment treatment can generally be transformed by a change in temperature. In the case of a lyotropic liquid crystal compound, the transition can also be caused by changing the composition ratio such as the amount of solvent.
Note that the conditions for heating the coating film are not particularly limited, but the heating temperature is preferably 50 to 150°C, and the heating time is preferably 10 seconds to 5 minutes.

Next, the coating film in which the polymerizable liquid crystal compound is oriented is subjected to a curing treatment to form an optically anisotropic layer.
The method of curing treatment is not particularly limited, and includes light irradiation treatment and heat treatment, with light irradiation being more preferred.
The type of light used during exposure is not particularly limited, but ultraviolet light is preferred.
The irradiation amount during exposure is not particularly limited, and is preferably 10 mJ/cm ² to 50 J/cm ² , more preferably 20 mJ/cm ² to 5 J/cm ² . Moreover, in order to promote the polymerization reaction, it may be carried out under heating conditions.

[Polarizer]
The polarizing plate of the present invention includes the optical film of the present invention or the optically anisotropic layer of the present invention (hereinafter, in the description of the polarizing plate of the present invention, it will be abbreviated as "the optical film of the present invention, etc."), a polarizer, It is a polarizing plate having

[Polarizer]
The polarizer included in the polarizing plate of the present invention is not particularly limited as long as it is a member that has the function of converting light into specific linearly polarized light, and conventionally known absorption type polarizers and reflection type polarizers can be used. .
As the absorption type polarizer, an iodine polarizer, a dye polarizer using a dichroic dye, a polyene polarizer, etc. are used. Iodine-based polarizers and dye-based polarizers include coating-type polarizers and stretched-type polarizers, and both can be applied, but polarized light produced by adsorbing iodine or dichroic dye to polyvinyl alcohol and stretching it Child is preferred.
In addition, as a method for obtaining a polarizer by stretching and dyeing a laminated film in which a polyvinyl alcohol layer is formed on a base material, Japanese Patent No. 5048120, Japanese Patent No. 5143918, Japanese Patent No. 4691205, and Publication No. 4751481 and Japanese Patent No. 4751486 are mentioned, and known techniques regarding these polarizers can also be preferably used.
As a coating type polarizer, WO2018/124198, WO2018/186503, WO2019/132020, WO2019/132018, WO2019/189345, JP 2019-197168, JP 2019-194685, and JP 2019-1 No. 39222 Publications are listed, and known techniques related to these polarizers can also be preferably used.
As the reflective polarizer, a polarizer in which thin films with different birefringences are laminated, a wire grid polarizer, a polarizer in which a cholesteric liquid crystal having a selective reflection region and a quarter-wave plate are combined, etc. are used.
Among these, polyvinyl alcohol-based resins (polymer containing -CH ₂ -CHOH- as a repeating unit; in particular, at least one selected from the group consisting of polyvinyl alcohol and ethylene-vinyl alcohol copolymers) have better adhesion. 1) is preferred.
Further, from the viewpoint of imparting crack resistance, the polarizer may have depolarization portions formed along opposing edges. Examples of the depolarization unit include Japanese Patent Application Laid-Open No. 2014-240970.
Further, the polarizer may have non-polarizing portions arranged at predetermined intervals in the longitudinal direction and/or the width direction. The non-polarized portion is a partially bleached portion. The arrangement pattern of the non-polarizing portions can be appropriately set depending on the purpose. For example, when the polarizer is cut to a predetermined size (cutting, punching, etc.) in order to attach it to an image display device of a predetermined size, the non-polarizing portion is placed at a position corresponding to the camera portion of the image display device. Examples of the arrangement pattern of the non-polarizing portion include Japanese Patent Application Laid-open No. 2016-27392.

The thickness of the polarizer is not particularly limited, but is preferably 3 to 60 μm, more preferably 3 to 30 μm, and even more preferably 3 to 10 μm.

The polarizing plate of the present invention may have other optical films, a protective film described below, and other functional layers in addition to the optical film of the present invention and the polarizer. The function of the functional layer is not particularly limited, and for example, it may be a layer having functions such as an adhesive layer, a stress relaxation layer, a flattening layer, an antireflection layer, a refractive index adjustment layer, and an ultraviolet absorption layer.
The protective film may be used on both sides of the polarizer, or may be used only on one side of the polarizer.
In addition, when the protective film is on the same side as the optical film, etc. of the present invention, an adhesive or adhesive may be applied between the polarizer and the optical film, or on the opposite side of the optical film, etc. from the polarizer. It may also be placed through the
The polarizing plate can be used as a circularly polarizing plate when the optically anisotropic layer of the optical film of the invention described above or the optically anisotropic layer of the invention is a λ/4 plate (positive A plate).
When using the polarizing plate as a circularly polarizing plate, the optically anisotropic layer described above is a λ/4 plate (positive A plate), and the angle between the slow axis of the λ/4 plate and the absorption axis of the polarizer described later is is preferably 30 to 60°, more preferably 40 to 50°, even more preferably 42 to 48°, and particularly preferably 45°.
Here, the "slow axis" of the λ/4 plate means the direction in which the refractive index is maximum within the plane of the λ/4 plate, and the "absorption axis" of the polarizer means the direction in which the absorbance is highest. do.
Further, the polarizing plate can also be used as an optical compensation film of an IPS (In-Plane-Switching) type or FFS (Fringe-Field-Switching) type liquid crystal display device.
When the polarizing plate is used as an optical compensation film for an IPS mode or FFS mode liquid crystal display device, the above-mentioned optically anisotropic layer is used as at least one plate of a laminate of a positive A plate and a positive C plate. It is preferable that the angle between the slow axis of the plate layer and the absorption axis of the polarizer be perpendicular or parallel. Specifically, the angle between the slow axis of the positive A plate layer and the absorption axis of the polarizer is preferably More preferably, the angle is 0-5° or 85-95°.
In addition, when the above optical compensation film has a polarizer, a positive C plate, and a positive A plate laminated in this order, the angle between the slow axis of the positive A plate and the absorption axis of the polarizer is parallel to each other. It is more preferable that
Similarly, when the optical compensation film has a polarizer, a positive A plate, and a positive C plate laminated in this order, the angle between the slow axis of the positive A plate and the absorption axis of the polarizer is More preferably, they are orthogonal.
When the polarizing plate of the present invention is used in a liquid crystal display device to be described later, it is preferable that the angle between the slow axis of the optically anisotropic layer and the absorption axis of the polarizer be parallel or orthogonal.
Note that in this specification, "parallel" does not necessarily require strict parallelism, but means that the angle formed by one side and the other side is less than 10 degrees. Further, in this specification, "orthogonal" does not necessarily require that they be strictly orthogonal, but means that the angle between one and the other is more than 80° and less than 100°.

〔Protective film〕
The material for the protective film is not particularly limited, and examples include cellulose acylate film (e.g., cellulose triacetate film, cellulose diacetate film, cellulose acetate butyrate film, cellulose acetate propionate film), polyacrylics such as polymethyl methacrylate, etc. Resin film, polyolefin such as polyethylene and polypropylene, polyester resin film such as polyethylene terephthalate and polyethylene naphthalate, polyether sulfone film, polyurethane resin film, polyester film, polycarbonate film, polysulfone film, polyether film, polymethylpentene film , polyetherketone film, (meth)acrylonitrile film, polyolefin, polymer with alicyclic structure (norbornene resin (Arton: trade name, manufactured by JSR Corporation), amorphous polyolefin (Zeonex: trade name, manufactured by Nippon Zeon Co., Ltd.) )), etc. Among these, cellulose acylate film is preferred.

The optical properties of the protective film are not particularly limited, but when the protective film is on the same side as the optical film of the present invention, it is preferable that the following formula is satisfied.
0nm≦Re(550)≦10nm
-40nm≦Rth(550)≦40nm

[Adhesive layer]
In the polarizing plate, an adhesive layer may be disposed between the optical film or the like of the present invention and the polarizer.
As for the material forming the adhesive layer, for example, the ratio of storage elastic modulus G' to loss elastic modulus G'' (tan δ=G''/G') measured with a dynamic viscoelasticity measuring device is 0.001 to 1. .5, including so-called adhesives and substances that tend to creep. Examples of the adhesive include, but are not limited to, polyvinyl alcohol adhesives.

[Adhesive layer]
In the polarizing plate, an adhesive layer may be disposed between the optical film or the like of the present invention and the polarizer.
As the adhesive layer, a curable adhesive composition that is cured by irradiation with active energy rays or heating is preferable.
Examples of the curable adhesive composition include a curable adhesive composition containing a cationically polymerizable compound and a curable adhesive composition containing a radically polymerizable compound.
The thickness of the adhesive layer is preferably 0.01 to 20 μm, more preferably 0.01 to 10 μm, and even more preferably 0.05 to 5 μm. If the thickness of the adhesive layer is within this range, no lifting or peeling will occur between the protective layer or optically anisotropic layer to be laminated and the polarizer, and adhesive strength with no practical problems can be obtained. Further, from the viewpoint of suppressing the generation of bubbles, the thickness of the adhesive layer is preferably 0.4 μm or more.
Further, from the viewpoint of durability, the bulk water absorption rate of the adhesive layer may be adjusted to 10% by mass or less, preferably 2% by mass or less. The bulk water absorption rate is measured according to the water absorption rate test method described in JIS K 7209.
As for the adhesive layer, for example, paragraphs [0062] to [0080] of JP-A-2016-35579 can be referred to, and the contents thereof are incorporated into the present specification.

[Easy adhesive layer]
In the polarizing plate, an easily adhesive layer may be disposed between the optical film of the present invention and the polarizer.
From the viewpoint of excellent adhesion between the optical film, etc. of the present invention and the polarizer, and furthermore, from the viewpoint of suppressing the occurrence of cracks in the polarizer, the storage elastic modulus of the easy-adhesive layer at 85°C is 1.0 × 10 ⁶ Pa. It is preferably 1.0×10 ⁷ Pa. Examples of constituent materials of the easily adhesive layer include polyolefin components and polyvinyl alcohol components. The thickness of the adhesive layer is preferably 500 nm to 1 μm.
As for the easy-adhesive layer, for example, paragraphs [0048] to [0053] of JP-A No. 2018-36345 can be referred to, and the contents thereof are incorporated into the specification of the present application.

[Image display device]
The image display device of the present invention is an image display device having the optical film of the present invention or the optically anisotropic layer of the present invention.
The display element used in the image display device is not particularly limited, and includes, for example, a liquid crystal cell, an organic electroluminescence (hereinafter abbreviated as "EL (Electro Luminescence)") display panel, a plasma display panel, and the like. Among these, liquid crystal cells and organic EL display panels are preferred, and liquid crystal cells are more preferred.
That is, as the image display device, a liquid crystal display device using a liquid crystal cell as a display element or an organic EL display device using an organic EL display panel as a display element is preferable, and a liquid crystal display device is more preferable.

[Liquid crystal display device]
A liquid crystal display device, which is an example of an image display device, includes the above-mentioned polarizing plate and a liquid crystal cell.
Note that among the polarizing plates provided on both sides of the liquid crystal cell, it is preferable to use the above-described polarizing plate as the front-side polarizing plate, and it is more preferable to use the above-mentioned polarizing plates as the front-side and rear-side polarizing plates.
The liquid crystal cell constituting the liquid crystal display device will be described in detail below.

<Liquid crystal cell>
The liquid crystal cells used in liquid crystal display devices are in VA (Vertical Alignment) mode, OCB (Optically Compensated Bend) mode, IPS (In-Plane-Switching) mode, FFS (Fringe-Field-Switching) mode, or TN (Twisted) mode. Nematic) mode is preferable, but is not limited thereto.
In a TN mode liquid crystal cell, rod-like liquid crystal molecules are substantially horizontally aligned when no voltage is applied, and are further twisted at an angle of 60 to 120 degrees. TN mode liquid crystal cells are most commonly used as color TFT liquid crystal display devices, and are described in numerous documents.
In a VA mode liquid crystal cell, rod-like liquid crystal molecules are aligned substantially vertically when no voltage is applied. VA mode liquid crystal cells include (1) narrowly defined VA mode liquid crystal cells in which rod-shaped liquid crystal molecules are aligned substantially vertically when no voltage is applied, and substantially horizontally when voltage is applied (Japanese Patent Application Laid-Open No. 2002-2002); In addition to (2) a multi-domain (MVA mode) liquid crystal cell (SID97, described in Digest of tech.Papers (Proceedings) 28 (1997) 845) in which VA mode is multi-domained to expand the viewing angle (described in Publication No. 176625) ), (3) Liquid crystal cell in a mode (n-ASM mode) in which rod-shaped liquid crystal molecules are aligned substantially vertically when no voltage is applied, and twisted and multi-domain aligned when a voltage is applied (Proceedings of the Japan Liquid Crystal Conference 58-59) (1998)), and (4) SURVIVAL mode liquid crystal cell (presented at LCD International 98). Further, the VA mode liquid crystal cell may be any of the PVA (Patterned Vertical Alignment) type, the optical alignment type (Optical Alignment), and the PSA (Polymer-Sustained Alignment) type. Details of these modes are described in Japanese Patent Application Laid-open No. 2006-215326 and Japanese Patent Application Publication No. 2008-538819.
In an IPS mode liquid crystal cell, rod-shaped liquid crystal molecules are aligned substantially parallel to the substrate, and when an electric field parallel to the substrate surface is applied, the liquid crystal molecules respond in a planar manner. In the IPS mode, a black display occurs when no electric field is applied, and the absorption axes of the pair of upper and lower polarizing plates are perpendicular to each other. A method of using an optical compensatory sheet to reduce leakage light during black display in an oblique direction and improve the viewing angle is disclosed in JP-A-10-54982, JP-A-11-202323, and JP-A-9-292522. JP-A-11-133408, JP-A-11-305217, and JP-A-10-307291.

[Organic EL display device]
An organic EL display device, which is an example of an image display device, includes, from the viewing side, a polarizer, a λ/4 plate (positive A plate) made of the above-mentioned optically anisotropic layer, and an organic EL display panel. Examples include embodiments in which the elements are arranged in this order.
Furthermore, an organic EL display panel is a display panel constructed using an organic EL element in which an organic light emitting layer (organic electroluminescence layer) is sandwiched between electrodes (between a cathode and an anode). The structure of the organic EL display panel is not particularly limited, and a known structure may be employed.

The present invention will be described in more detail below based on Examples. The materials, usage amounts, proportions, processing details, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the Examples shown below.

[Example 1]
[Preparation of cellulose acylate film (support)]
A cellulose acylate dope having the following composition was placed in a mixing tank, stirred, and further heated at 90° C. for 10 minutes.
Thereafter, the resulting composition was filtered through a filter paper with an average pore size of 34 μm and a sintered metal filter with an average pore size of 10 μm to prepare a dope.
The solid content concentration of the dope is 23.5% by mass, the amount of plasticizer added is the ratio to cellulose acylate, and the solvent of the dope is methylene chloride/methanol/butanol = 81/18/1 (mass ratio). .

――――――――――――――――――――――――――――――――
Cellulose acylate dope――――――――――――――――――――――――――――――――
Cellulose acylate (degree of acetyl substitution 2.86, viscosity average degree of polymerization 310)
100 parts by weight Sugar ester compound 1 (shown in chemical formula (S4)) 6.0 parts by weight Sugar ester compound 2 (shown in chemical formula (S5)) 2.0 parts by weight Silica particle dispersion (AEROSIL R972, Nippon Aerosil Co., Ltd.) made)
0.1 part by mass solvent (methylene chloride/methanol/butanol)
――――――――――――――――――――――――――――――――

The dope prepared above was cast using a drum film forming machine.
Specifically, the dope was cast from a die so as to be in contact with a metal support cooled to 0° C., and then the obtained web (film) was peeled off. Note that the drum was made of SUS.
Next, the web (film) obtained by casting is peeled from the drum, and then heated at 30 to 40°C during film transport, using a tenter machine that clips both ends of the web with clips and transports it. Dry for a minute. Subsequently, the web was post-dried by zone heating while being rolled.
Next, the obtained web was knurled and then wound up.

(alkali saponification treatment)
The wound web was passed through a dielectric heating roll at a temperature of 60°C to raise the film surface temperature to 40°C, and then an alkaline solution having the composition shown below was applied to the band surface of the film using a bar coater. It was coated at a coating amount of 14 ml/m ² and conveyed for 10 seconds under a steam-type far-infrared heater manufactured by Noritake Company Limited, which was heated to 110°C. Subsequently, 3 ml/m ² of pure water was applied using the same bar coater. Next, washing with water using a fountain coater and draining using an air knife were repeated three times, and then the film was transported to a drying zone at 70° C. for 10 seconds to dry, thereby producing a cellulose acylate film subjected to alkali saponification treatment.

――――――――――――――――――――――――――――――――
Alkaline solution――――――――――――――――――――――――――――――――
- Potassium hydroxide 4.7 parts by mass - Water 15.8 parts by mass - Isopropanol 63.7 parts by mass - Surfactant SF-1: C ₁₄ H ₂₉ O (CH ₂ CH ₂ O) ₂₀ H 1.0 parts by mass・Propylene glycol 14.8 parts by mass――――――――――――――――――――――――――――――

[Formation of alignment film]
A composition for forming an alignment film having the following composition was continuously applied to the surface of the cellulose acylate film that had been subjected to the alkali saponification treatment using a #14 wire bar. It was dried with warm air at 60°C for 60 seconds and then with warm air at 100°C for 120 seconds to obtain an alignment film.

――――――――――――――――――――――――――――――――
Composition for forming alignment film――――――――――――――――――――――――――――――
・Specific polymer: Modified polyvinyl alcohol-1 below 100 parts by mass ・Specific additive: Sodium dodecyl sulfate 1.0 parts by mass ・Photopolymerization initiator below 7.5 parts by mass ・Curing agent below 1.75 parts by mass ・Water 2620 parts by mass 873 parts by mass of methanol――――――――――――――――――――――――――――――

Modified polyvinyl alcohol-1 [In the following formula, the numerical value written for each repeating unit represents the content (mol%) of each repeating unit with respect to all repeating units. ]

Photoinitiator

hardening agent

[Formation of optically anisotropic layer]
The alignment film produced above was continuously subjected to rubbing treatment. At this time, the longitudinal direction of the long film was parallel to the transport direction, and the angle between the film longitudinal direction (transport direction) and the rotation axis of the rubbing roller was 78°. If the longitudinal direction of the film (conveyance direction) is 90°, and the clockwise direction is expressed as a positive value with the film width direction as the reference (0°) when observed from the film side, the rotation axis of the rubbing roller is at 12°. . In other words, the position of the rotation axis of the rubbing roller is a position rotated 78 degrees counterclockwise with respect to the longitudinal direction of the film.

Using the rubbed cellulose acylate film with an alignment film as a substrate, a composition for forming an optically anisotropic layer (1) containing a rod-like liquid crystal compound having the following composition was applied using a Giesser coating machine to form a composition. formed a layer. The absolute value of the weighted average helical inducing force of the chiral agent in the composition layer was 0.0 μm ⁻¹ .
Next, the obtained composition layer was heated at 95° C. for 60 seconds. By this heating, the rod-like liquid crystal compound of the composition layer was oriented in a predetermined direction.
Thereafter, the composition layer was irradiated with ultraviolet rays (irradiation amount: 25 mJ/ ^cm2 ).
Subsequently, the obtained composition layer was heated at 95° C. for 10 seconds.
Thereafter, a nitrogen purge was performed, and the composition layer was irradiated with ultraviolet rays at 80°C with an oxygen concentration of 100 volume ppm using a metal halide lamp (manufactured by Eye Graphics Co., Ltd.) (irradiation amount: 500 mJ/cm). ² ) An optically anisotropic layer in which the alignment state of the liquid crystal compound was fixed was formed. In this way, an optical film (F-1) was produced.

――――――――――――――――――――――――――――――――
Composition for forming optically anisotropic layer (1)
――――――――――――――――――――――――――――――――
・The following rod-like liquid crystal compound (A) 80 parts by mass ・The following rod-like liquid crystal compound (B) 17 parts by mass ・The following polymerizable compound (C) 3 parts by mass ・Ethylene oxide modified trimethylolpropane triacrylate (V#360, Osaka Organic Chemical) Co., Ltd.) 4 parts by mass Photopolymerization initiator (Irgacure 819, manufactured by BASF) 3 parts by mass 0.47 parts by mass of the following left-handed chiral agent (L2) 0.42 parts by mass of the following right-handed chiral agent (R2) parts・Polymer (A) below 0.08 parts by mass・Methyl isobutyl ketone 78 parts by mass・Ethyl propionate 78 parts by mass―――――――――――――――――――― ――――――――――

Rod-shaped liquid crystal compound (A) [Mixture of the following liquid crystal compounds (RA) (RB) (RC) at a ratio of 84:14:2 (mass ratio)]

Rod-shaped liquid crystal compound (B)

Polymerizable compound (C)

Left-handed chiral agent (L2)

Right-handed chiral agent (R2)

Polymer (A) [Fluorine part: 39% by mass, Mesogen part: 61% by mass]

The optical film (F-1) produced above was cut parallel to the rubbing direction, and the optically anisotropic layer was observed from the cross-sectional direction using a polarizing microscope. The thickness of the optically anisotropic layer is 2.7 μm, and the region (second region) with a thickness (d2) of 1.3 μm on the substrate side of the optically anisotropic layer has a homogeneous orientation with no twist angle, and is optically anisotropic. In a region (first region) with a thickness (d1) of 1.4 μm on the air side (opposite side to the substrate) of the liquid crystal layer, the liquid crystal compound was twisted and oriented.
The optical properties of the optical film (F-1) were determined using Axoscan from Axometrics and the company's analysis software (Multi-Layer Analysis). The product (Δn2d2) of Δn2 and thickness d2 at a wavelength of 550 nm in the second region is 177 nm, the twist angle of the liquid crystal compound is 0°, and the alignment axis angle of the liquid crystal compound with respect to the long longitudinal direction is -11 on the side in contact with the substrate. °, and the side in contact with the first region was −11°.
Further, the product (Δn1d1) of Δn1 and thickness d1 at a wavelength of 550 nm in the first region is 180 nm, the twist angle of the liquid crystal compound is 80°, and the orientation axis angle of the liquid crystal compound with respect to the long longitudinal direction is The contact side was -11° and the air side was -91°.

[Examples 2 to 15 and Comparative Examples 1 to 3]
An optical film was produced in the same manner as in Example 1, except that the types and amounts of additives were changed as shown in Table 1 below.

[Example 16]
An optical film was produced in the same manner as in Example 2, except that modified polyvinyl alcohol-1 was changed to modified polyvinyl alcohol-2 shown below.
Next, the support and alignment film of the produced optical film were peeled off to isolate the optically anisotropic layer.

Modified polyvinyl alcohol-2 [In the following formula, the numerical value written for each repeating unit represents the content (mol%) of each repeating unit with respect to all repeating units. ]

[Example 17]
An optical film was produced in the same manner as in Example 2, except that modified polyvinyl alcohol-1 was changed to modified polyvinyl alcohol-3 shown below.
Next, the adhesive side of the adhesive with a separator on one side and the optically anisotropic layer side of the prepared optical film are bonded together, and the optical anisotropic layer is peeled off from the optical film. The layer was transferred to the adhesive.

Modified polyvinyl alcohol-3 [In the following formula, the numerical value written for each repeating unit represents the content (mol%) of each repeating unit with respect to all repeating units. ]

[Example 18 and 19]
An optical film was produced in the same manner as in Example 2, except that modified polyvinyl alcohol-1 was changed to those shown in Table 1 below. The details of the polymers used in Examples 18 and 19 are as follows.
・Polyacrylic acid: Aqualic (registered trademark) HL (manufactured by Nippon Shokubai Co., Ltd.)
・Modified polyamide: AQ nylon P70 (manufactured by Toray Industries)

[Example 20]
Example 2 except that the composition for forming an optically anisotropic layer (1) was changed to the composition for forming an optically anisotropic layer (2) shown below, and the optically anisotropic layer was formed under the following conditions. An optical film was prepared in the same manner as above.
Specifically, if the longitudinal direction of the film (conveyance direction) is 90° and the clockwise direction is expressed as a positive value with the width direction of the film as the reference (0°) when observed from the alignment film side, then the rotation of the rubbing roller The axis was set at -17.5°, and rubbing treatment was performed to obtain an alignment film. The composition for forming an optically anisotropic layer (2) was continuously applied onto the alignment film using a Giesser coating machine. The transport speed of the film was 26 m/min. To dry the solvent and ripen the discotic liquid crystal compound for orientation, the coating film on the alignment film was heated with hot air at 130°C for 90 seconds, then heated with hot air at 100°C for 60 seconds, and then heated at 80°C. UV (ultraviolet) irradiation was performed at 300 mJ/cm ² to fix the orientation of the liquid crystal compound, forming an optically anisotropic layer with a thickness of 2.0 μm. The average inclination angle of the disc surface of the discotic liquid crystal compound with respect to the film surface was 90°, and it was confirmed that the discotic liquid crystal compound was oriented perpendicularly to the film surface.
In addition, the angle of the slow axis is parallel to the rotation axis of the rubbing roller, 0° in the film width direction (90° in the longitudinal direction of the film, clockwise with respect to the film width direction when observed from the optically anisotropic layer side). (expressed as a positive value), it was -17.5°. The in-plane retardation of the optically anisotropic layer at a wavelength of 550 nm is 240 nm, and the optically anisotropic layer exhibits forward wavelength dispersion.

――――――――――――――――――――――――――――――――
Composition for forming optically anisotropic layer (2)
――――――――――――――――――――――――――――――――
・The following discotic liquid crystal compound-1 80 parts by mass ・The following discotic liquid crystal compound-2 20 parts by mass ・The following alignment film interface alignment agent-1 1.6 parts by mass ・The following fluorine-containing compound (F-1) 0.21 parts by mass 0.075 parts by mass of the following fluorine-containing compound (F-2) 0.1 parts by mass of the following fluorine-containing compound (F-3) 5 parts by mass of ethylene oxide-modified trimethylolpropane triacrylate 5 parts by mass of photopolymerization initiator (Irgacure) 907, manufactured by BASF) 4 parts by mass ・Methyl ethyl ketone 200 parts by mass ――――――――――――――――――――――――――――――

Discotic liquid crystal compound-1

Discotic liquid crystal compound-2

Alignment film interface alignment agent-1

Fluorine-containing compound (F-1)

Fluorine-containing compound (F-2)

Fluorine-containing compound (F-3)

In addition, in the above fluorine-containing compounds (F-1) to (F-3), the numerical value written next to each repeating unit (for example, in the fluorine-containing compound (F-1), "25", "25", and , "50") represents the content (mol%) of each repeating unit with respect to all repeating units.

[Example 21]
Except that the composition for forming an optically anisotropic layer (1) was changed to the composition for forming an optically anisotropic layer (3) shown below, and the thickness of the optically anisotropic layer formed was changed to 2.6 μm. An optical film was produced in the same manner as in Example 2.

――――――――――――――――――――――――――――――――
Composition for forming optically anisotropic layer (3)
――――――――――――――――――――――――――――――――
- 80 parts by mass of the above rod-like liquid crystal compound (A) - 17 parts by mass of the above-mentioned rod-like liquid crystal compound (B) - 3 parts by mass of the above polymerizable compound (C) - Ethylene oxide-modified trimethylolpropane triacrylate (V#360, 4 parts by mass of photopolymerization initiator (Irgacure 819, manufactured by BASF) 0.46 parts by mass of the above left-handed chiral agent (L2) 0.46 parts by mass of the above right-handed chiral agent (R2) ) 0.41 parts by mass - 0.08 parts by mass of the above polymer (A) - 0.38 parts by mass of the following polymer (B) - 117 parts by mass of methyl isobutyl ketone - 23 parts by mass of ethyl propionate - 16 parts by mass of cyclohexane --- ――――――――――――――――――――――――――――――

Polymer B

[Example 22]
The composition for forming an optically anisotropic layer (1) was changed to the composition for forming an optically anisotropic layer (4) shown below, and the position of the rotation axis of the rubbing roller was changed from -17.5° to +12.5°. An optical film was produced in the same manner as in Example 20, except that the following was changed.
The thickness of the optically anisotropic layer obtained was 1.0 μm. The average inclination angle of the long axis of the rod-like liquid crystal compound with respect to the film plane was 0°, and it was confirmed that the liquid crystal compound was oriented horizontally with respect to the film plane. In addition, the angle of the slow axis is perpendicular to the rotation axis of the rubbing roller, 0° in the film width direction (90° in the longitudinal direction of the film, clockwise with respect to the film width direction when observed from the optically anisotropic layer C side). (The direction is expressed as a positive value.), it was -77.5°. The in-plane retardation of the optically anisotropic layer at a wavelength of 550 nm is 116 nm, and the optically anisotropic layer exhibits normal wavelength dispersion.

――――――――――――――――――――――――――――――――
Composition for forming optically anisotropic layer (4)
――――――――――――――――――――――――――――――――
- 100 parts by mass of the above rod-shaped liquid crystal compound (A) - 6 parts by mass of photopolymerization initiator (Irgacure 907, manufactured by BASF) - 0.25 parts by mass of the above fluorine-containing compound (F-1) - 0.25 parts by mass of the above fluorine-containing compound (F-1) -2) 0.1 parts by mass 4 parts by mass of ethylene oxide-modified trimethylol propane triacrylate 337 parts by mass of methyl ethyl ketone ―――――――――――――――――――――― ――――――――

[Examples 23 and 24]
An optical film was produced in the same manner as in Example 1, except that the types and amounts of additives were changed as shown in Table 2 below.

[Examples 25 to 30 and Comparative Example 4]
An optical film was produced in the same manner as in Example 1, except that the types and amounts of additives were changed as shown in Table 2 below. The synthesis method and structure of copolymer A, copolymer B, polymer C, copolymer D, and copolymer E used as additives in Examples 25 to 30 and Comparative Example 4 are as follows. It is.

<Synthesis method of copolymer A>
17.5 g of ethanol (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) was placed in a 200 mL three-necked flask equipped with a stirrer, a cooling tube, a nitrogen introduction tube, and a thermometer, and heated to 70°C.
Next, under a nitrogen flow, 21.0 g of NK Ester M-230G (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), 9.0 g of Blenmar PSE-1300 (manufactured by NOF Chemical Co., Ltd.), and 2,2'-azobis(iso) A mixed solution of 1.4 g of butyronitrile (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) and 50.4 g of ethanol was added dropwise over 3 hours.
After the dropwise addition, a solution of 0.1 g of 2,2'-azobis(isobutyronitrile) dissolved in 5.7 g of ethanol was added. Thereafter, it was aged at 70°C for 3 hours. Copolymer A represented by the following formula was obtained by raising the internal temperature to 78° C. and aging for further 8 hours. The weight average molecular weight of the obtained copolymer A was 12,600, and the molecular weight distribution was 3.3.

<Synthesis method of copolymer B>
A copolymer represented by the following formula was prepared in the same manner as for copolymer A, except that NK ester M-230G used in the synthesis of copolymer A was changed to methacrylic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). Polymer B was obtained. Copolymer B had a weight average molecular weight of 10,800 and a molecular weight distribution of 3.1. Copolymer B was obtained by neutralizing with sodium hydroxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).

<Synthesis method of polymer C>
Polymer C represented by the following formula was obtained in the same manner as Copolymer A except that Blenmar PSE-1300 used in the synthesis of Copolymer A was not used. Polymer C had a weight average molecular weight of 14,800 and a molecular weight distribution of 2.3.

<Synthesis method of copolymer D>
A copolymer represented by the following formula was prepared in the same manner as for copolymer A, except that Blenmar PSE-1300 used in the synthesis of copolymer A was changed to stearyl methacrylate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). Combined D was obtained. Copolymer D had a weight average molecular weight of 14,200 and a molecular weight distribution of 2.5.

<Synthesis method of copolymer E>
Copolymer E represented by the following formula was obtained in the same manner as Copolymer B, except that neutralization was eliminated in the synthesis of Copolymer B. Copolymer E had a weight average molecular weight of 10,800 and a molecular weight distribution of 3.1.

[Example 31]
An optical film was produced in the same manner as in Example 26, except that the composition for forming an optically anisotropic layer (1) was changed to the composition for forming an optically anisotropic layer (5).
――――――――――――――――――――――――――――――――
Composition for forming an optically anisotropic layer (5)
――――――――――――――――――――――――――――――――
- 80 parts by mass of the rod-like liquid crystal compound (A) - 17 parts by mass of the rod-like liquid crystal compound (B) - 3 parts by mass of the polymerizable compound (C) - Ethylene oxide-modified trimethylolpropane triacrylate (V#360, Osaka Organic Chemical) Co., Ltd.) 4 parts by mass Photopolymerization initiator (Irgacure 819, manufactured by BASF) 3 parts by mass - The above left-handed chiral agent (L2) 0.47 parts by mass - The above right-handed chiral agent (R2) 0.42 parts by mass 0.08 parts by mass of the above polymer (A) 0.10 parts by mass of lithium bis(trifluoromethanesulfonyl)imide (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) 78 parts by mass of methyl isobutyl ketone 78 parts by mass of ethyl propionate Department――――――――――――――――――――――――――――――――

[Example 32]
An optical film was produced in the same manner as in Example 26, except that the composition for forming an alignment film was changed as follows.
――――――――――――――――――――――――――――――――
Composition for forming alignment film――――――――――――――――――――――――――――――
・Specific polymer: 100 parts by mass of the above modified polyvinyl alcohol-1 ・Specific additive: 2.0 parts by mass of the above copolymer A ・7.5 parts by mass of the above photopolymerization initiator ・1.75 parts by mass of the above curing agent ・Lithium Bis(trifluoromethanesulfonyl)imide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 1.00 parts by mass, water 2620 parts by mass, methanol 873 parts by mass―――――――――――――――― ――――――――――――――――

[evaluation]
The following evaluations were performed on the produced optical film or optically anisotropic layer, the alignment film in the middle of production, and the like. The results are shown in Tables 1 and 2 below.

[Muddy]
The composition for forming an alignment film was visually observed by transmitting light, and was observed according to the following criteria.
A: The coating liquid is transparent.
B: The coating liquid is cloudy.

[Dynamic friction coefficient]
The dynamic friction coefficient was measured by measuring the load applied when rolling the SUS ball while applying a 100 g load to the surface of the alignment film.

[Orientation]
The optically anisotropic layer in the obtained optical film was randomly observed under a polarizing microscope in a crossed nicol state at a magnification of 50 times (field size: 1715 x 1280 μm), and each field was classified into the following three categories.
I: No optical defects observed.
II: Slight optical defects are observed, but at a level that causes no practical problems.
III: Many optical defects were observed, and the level was problematic in practice.
The 10 visual fields were evaluated in the following five stages.
A: All 10 fields are I or II, and the number of II fields is 0 to 2 fields.
B: All 10 fields are I or II, and the number of II fields is 3 to 5.
C: All 10 visual fields are I or II, and the number of II visual fields is 6 to 10.
D: III is included in 10 visual fields, and the number of III visual fields is 1 to 5.
E: 10 visual fields include III, and the number of III visual fields is 6 to 10.

[Bright spot defect]
Two polarizing plates were placed on top of the Scherkasten in a crossed nicol state, and the obtained optical film (observation area: 1×1 m) was sandwiched between the two polarizing plates to allow light to pass through the Scherkasten. For Examples 16 and 17, the adhesive side of the adhesive-attached optically anisotropic layer with the separator removed was pasted on a polarizing plate, and the same state was obtained by placing another polarizing plate in a crossed nicol state. I let it happen. The optical film was observed from above the polarizing plate using a magnifying glass, and defects with a diameter of 100 μm or more were marked. A cross-section was cut using a microtome so as to pass through the center of the marked defect, and optical microscopic observation was performed from the cross-sectional direction. Defects in which foreign matter was observed in the optically anisotropic layer were counted and evaluated according to the following criteria.
A: 2 or less defects B: 3 to 4 defects C: 5 to 8 defects D: 8 to 20 defects E: 21 or more defects

[Component analysis of bright spot defects]
For Examples 16 and 17, ten bright spot defects were collected, and the central part of the bright spot was etched in the depth direction of the optically anisotropic layer using an Ar+ cluster gun, while time-of-flight secondary ion mass was etched. Analyze the components in the depth direction using an analyzer (TOF-SIMS) (IONTOF's "SIMS5"), and check the presence of additives with alkyl groups and polymers without alkyl groups from the generated fragment ions. did. It was determined that the component was detected when the component was detected in four or more defects.

From the results shown in Tables 1 and 2, it can be seen that when specific additives are not blended into the composition for forming an alignment film, or when additives that do not fall under the category of specific additives are blended, the liquid crystal compound in the optically anisotropic layer is Although the orientation was good, it was found that the occurrence of bright spot defects could not be suppressed (Comparative Examples 1 to 4).
On the other hand, when an alignment film is formed using a composition for forming an alignment film containing a specific additive and a specific polymer, the alignment of the liquid crystal compound in the optically anisotropic layer is improved, and the bright spot defects are reduced. It was also found that the occurrence of the disease could be suppressed (Examples 1 to 30).
In particular, from a comparison between Example 1 and Example 14, when the alkyl group of the specific additive has 12 to 22 carbon atoms, the orientation of the liquid crystal compound in the optically anisotropic layer can be improved. Do you get it.
Further, from a comparison between Example 1 and Example 15, it was found that when the specific additive has a hydrophilic group, the orientation of the liquid crystal compound in the optically anisotropic layer becomes better.
Moreover, from the comparison of Examples 2, 18, and 19, when the specific polymer is polyvinyl alcohol or modified polyvinyl alcohol, the orientation of the liquid crystal compound in the optically anisotropic layer is better, and bright spot defects in the optical film are reduced. It was found that the outbreak could be further suppressed.
In addition, from the comparison between Example 1 and Example 25 and the comparison between Example 4 and Example 26, it was found that when the specific additive is a polymer compound, bright spot defects can be reduced while maintaining excellent orientation. It was found that the outbreak could be further suppressed.
Furthermore, from a comparison between Example 23 and Example 24, it was found that the occurrence of bright spot defects can be further suppressed when the arbitrary hydrophilic group of the specific additive is a neutralized product such as an ionic carboxylate. I understand.
Although not shown in Table 2, it was found that Examples 31 and 32 also had good orientation of the liquid crystal compound in the optically anisotropic layer, and also suppressed the occurrence of bright spot defects.

Claims (17)

1. An optical film having an alignment film and an optically anisotropic layer,
   The optically anisotropic layer is a layer formed using an optically anisotropic layer forming composition containing a polymerizable liquid crystal compound,
   The alignment film is a film formed using an alignment film forming composition containing an additive having an alkyl group having 5 to 29 carbon atoms and a polymer having no alkyl group having 5 to 29 carbon atoms. An optical film.
2. The optical film according to claim 1, wherein the additive has a hydrophilic group.
3. The optical film according to claim 1, wherein the additive has an alkyl group having 12 to 22 carbon atoms.
4. The optical film according to claim 1, wherein the polymer is polyvinyl alcohol or modified polyvinyl alcohol.
5. An optically anisotropic layer formed using an optically anisotropic layer forming composition containing a polymerizable liquid crystal compound,
   In the optically anisotropic layer, there are 1 to 80 bright spot defects/10 m ² of 100 μm or more, and the nucleus of the bright spot defects has an alkyl group having a carbon number of 5 to 29; An optically anisotropic layer containing a polymer having 5 to 29 carbon atoms and having no alkyl group.
6. The optically anisotropic layer according to claim 5, wherein the additive has a hydrophilic group.
7. The optically anisotropic layer according to claim 5, wherein the additive has an alkyl group having 12 to 22 carbon atoms.
8. The optically anisotropic layer according to claim 5, wherein the polymer is polyvinyl alcohol or modified polyvinyl alcohol.
9. A composition for forming an alignment film containing an additive having an alkyl group having 5 to 29 carbon atoms and a polymer having no alkyl group having 5 to 29 carbon atoms.
10. The composition for forming an alignment film according to claim 9, wherein the additive has a hydrophilic group.
11. The composition for forming an alignment film according to claim 9, wherein the additive has an alkyl group having 12 to 22 carbon atoms.
12. The composition for forming an alignment film according to claim 9, wherein the polymer is polyvinyl alcohol or modified polyvinyl alcohol.
13. An alignment film forming step of forming an alignment film on a support using the composition for forming an alignment film according to any one of claims 9 to 12;
    a rubbing step of applying a rubbing treatment to the alignment film;
    an optically anisotropic layer forming step of forming an optically anisotropic layer on the alignment film subjected to the rubbing treatment using an optically anisotropic layer forming composition containing a polymerizable liquid crystal compound;
    A method for producing an optical film, comprising:
14. A polarizing plate comprising the optical film according to any one of claims 1 to 4, or the optically anisotropic layer according to any one of claims 5 to 8, and a polarizer.
15. An image display device comprising the optical film according to any one of claims 1 to 4 or the optically anisotropic layer according to any one of claims 5 to 8.
16. The image display device according to claim 15, which is a liquid crystal display device.
17. The image display device according to claim 15, which is an organic EL display device.